U.S. patent number 11,096,179 [Application Number 16/454,173] was granted by the patent office on 2021-08-17 for communication system for alleviating interference arising due to coexistence.
This patent grant is currently assigned to NEC CORPORATION. The grantee listed for this patent is NEC Corporation. Invention is credited to Jagdeep Singh Ahluwalia, Neeraj Gupta, Kenji Kawaguchi.
United States Patent |
11,096,179 |
Ahluwalia , et al. |
August 17, 2021 |
Communication system for alleviating interference arising due to
coexistence
Abstract
A communication apparatus is disclosed, which comprises a base
station module and an access point module for providing wireless
connectivity to a communication network to at least one mobile
communication device; an interface for coupling the base station
module and the access point module for performing at least one of:
a channel restriction operation; a power restriction operation; an
intelligent uplink scheduling operation; a carrier frequency
reselection operation; and a traffic steering operation; whereby
alleviating an interference arising due to coexistence of the base
station module and the access point module.
Inventors: |
Ahluwalia; Jagdeep Singh
(Sutton, GB), Kawaguchi; Kenji (Tokyo, JP),
Gupta; Neeraj (Sutton, GB) |
Applicant: |
Name |
City |
State |
Country |
Type |
NEC Corporation |
Tokyo |
N/A |
JP |
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Assignee: |
NEC CORPORATION (Tokyo,
JP)
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Family
ID: |
51266528 |
Appl.
No.: |
16/454,173 |
Filed: |
June 27, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190320441 A1 |
Oct 17, 2019 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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15316927 |
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10362581 |
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PCT/JP2015/067377 |
Jun 10, 2015 |
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Foreign Application Priority Data
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Jun 12, 2014 [GB] |
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1410538 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
16/14 (20130101); H04W 76/15 (20180201); H04W
88/10 (20130101); H04W 72/0486 (20130101); H04W
72/1215 (20130101); H04W 84/042 (20130101); H04W
52/367 (20130101); H04W 84/045 (20130101); H04W
84/12 (20130101); Y02D 30/70 (20200801); H04W
92/20 (20130101); H04W 52/38 (20130101) |
Current International
Class: |
H04L
12/28 (20060101); H04W 72/04 (20090101); H04W
16/14 (20090101); H04W 76/15 (20180101); H04W
88/10 (20090101); H04W 72/12 (20090101); H04J
1/16 (20060101); H04W 84/04 (20090101); H04W
92/20 (20090101); H04W 84/12 (20090101) |
Field of
Search: |
;370/252,278,329,430 |
References Cited
[Referenced By]
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WO |
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Primary Examiner: Pezzlo; John
Attorney, Agent or Firm: Sughrue Mion, PLLC
Parent Case Text
The present application is a Continuation application of Ser. No.
15/316,927 filed on Dec. 7, 2016, which is a National Stage Entry
of PCT/JP2015/067377 filed on Jun. 10, 2015, which claims priority
from United Kingdom Patent Application 1410538.1 filed on Jun. 12,
2014, the contents of all of which are incorporated herein by
reference, in their entirety.
Claims
The invention claimed is:
1. An eNB comprising: a transceiver configured to communicate with
a user equipment (UE) and configured to provide Long Term Evolution
(LTE) connectivity for the UE, the UE configured to use radio
resources of an LTE network and a wireless local area network
(WLAN); and a controller configured to: request, over a dedicated
interface, to a communication device for providing a connectivity
between the UE and the WLAN, a load information and a channel
utilization time information of the WLAN; receive, over the
dedicated interface, the requested load information and the
requested channel utilization time information from the
communication device; and receive, from the communication device
over the dedicated interface, WLAN information identifying at least
one channel or frequency band of the WLAN.
2. The eNB according to claim 1 wherein the load information
comprises information identifying a number of UEs served by the
communication device.
3. The eNB according to claim 1 wherein the load information
comprises information identifying an available capacity of the
communication device.
4. A communication apparatus comprising: a transceiver configured
to communicate with a user equipment (UE) and configured to provide
a wireless local area network (WLAN) connectivity for the UE, the
UE configured to use radio resources of a Long Term Evolution (LTE)
network and the WLAN; and a controller configured to: receive, over
a dedicated interface, from an eNB for providing a connectivity
between the UE and the LTE network, a request for a load
information and a channel utilization time information of the WLAN;
send, over the dedicated interface, the load information and the
channel utilization time information to the eNB in accordance with
the request; and send, to the eNB over the dedicated interface,
WLAN information identifying at least one channel or frequency band
of the WLAN.
5. A method performed by an eNB comprising a communication module
configured to communicate with a user equipment (UE) and configured
to provide Long Term Evolution (LTE) connectivity for the UE, the
UE configured to use radio resources of an LTE network and a
wireless local area network (WLAN), the method comprising:
requesting, over a dedicated interface, to a communication device
for providing a connectivity between the UE and the WLAN, a load
information and a channel utilization time information of the WLAN;
receiving, over the dedicated interface, the requested load
information and the requested channel utilization time information
from the communication device; and receiving, from the
communication device over the dedicated interface, WLAN information
identifying at least one channel or frequency band of the WLAN.
6. A method performed by a communication device configured to
communicate with a user equipment (UE) and configured to provide a
wireless local area network (WLAN) connectivity for the UE, the UE
configured to use radio resources of a Long Term Evolution (LTE)
network and the WLAN, the method comprising: receiving, over a
dedicated interface, from an eNB for providing a connectivity
between the UE and the LTE network, a request for a load
information and a channel utilization time information of the WLAN;
sending, over the dedicated interface, the load information and the
channel utilization time information to the eNB in accordance with
the request; and sending, to the eNB over the dedicated interface,
WLAN information identifying at least one channel or frequency band
of the WLAN.
Description
TECHNICAL FIELD
The present invention relates to radio access networks in a
cellular or wireless telecommunication network, and particularly
but not exclusively to networks operating according to the 3GPP
standards or equivalents or derivatives thereof. The invention has
particular although not exclusive relevance to the Long Term
Evolution (LTE) of UTRAN (called Evolved Universal Terrestrial
Radio Access Network (E-UTRAN)) and to operation of dual mode base
stations operating in accordance with both LTE and non-LTE radio
technologies.
BACKGROUND ART
In a cellular communication network, mobile devices (also known as
User Equipment (UE) or mobile terminals, such as mobile telephones)
communicate with remote servers or with other mobile devices via
base stations. An LTE base station is also known as an `enhanced
NodeB` (eNB), which is coupled to an LTE core network also known as
an Enhanced Packet Core (EPC) network.
In their communication with each other, LTE mobile devices and base
stations use licensed radio frequencies, which are typically
divided into frequency bands and/or time blocks. Depending on
various criteria (such as the amount of data to be transmitted,
radio technologies supported by the mobile device, expected quality
of service, subscription settings, etc.), each base station is
responsible for controlling the transmission timings, frequencies,
transmission powers, modulations, etc. employed by the mobile
devices attached to the base station. In order to minimise
disruption to the service and to maximise utilisation of the
available bandwidth, the base stations continuously adjust their
own transmission power and also that of the mobile devices. Base
stations also assign frequency bands and/or time slots to mobile
devices, and also select and enforce the appropriate transmission
technology to be used between the base stations and the attached
mobile devices. By doing so, base stations also reduce or eliminate
any harmful interference caused by mobile devices to each other or
to the base stations.
Current mobile devices typically support multiple radio
technologies, not only LTE. The mobile devices might include, for
example, transceivers and/or receivers operating in the Industrial,
Scientific and Medical (ISM) radio bands, such as Bluetooth or
Wi-Fi transceivers. The term `Bluetooth` refers to the standards
developed by the Bluetooth Special Interest Group, and the term
`Wi-Fi` refers to the 802.11 family of standards developed by the
Institute of Electrical and Electronics Engineers (IEEE). If such a
non-LTE communication technology is supported, instead of
communicating via LTE base stations, mobile devices may also
communicate with remote servers or with other mobile devices using
non-LTE communication means, e.g. using an appropriate ISM
communication technology. For example, the mobile devices may
communicate via an access point (e.g. a Wi-Fi AP) operating in
accordance with the 802.11 family of standards by the Institute of
Electrical and Electronics Engineers (IEEE).
Recently, a so-called `dual mode` base station has been introduced
comprising an LTE home base station (HeNB) part (e.g. a pico/femto
base station or other low-power node) and a non-LTE access point
part (e.g. a Wi-Fi AP). Such a combined HeNB/AP base station may
also sometimes be referred to as a dual mode femto access point
(FAP) or dual FAP.
ISM and other radio technologies (hereafter commonly referred to as
non-LTE technologies) use frequency bands close to or partially
overlapping with the LTE frequency bands, as illustrated in FIG.
12. Some of these non-LTE frequency bands are licensed for a
particular use (e.g. Global Positioning Systems (GPS) bands) or
might be unlicensed bands and can be used by a number of radio
technologies (such as Bluetooth and Wi-Fi standards using the same
range of ISM frequency bands). The manner in which these non-LTE
frequency bands are used are, therefore, not covered by the LTE
standards and are not controlled by the LTE base stations (e.g. a
HeNB of a dual FAP). However, transmissions in the non-LTE
frequency bands might, nevertheless, still cause undesired
interference to (or suffer undesired interference resulting from)
transmissions in the LTE bands, particularly in the overlapping or
neighbouring frequency bands.
In particular, such undesired interference may be experienced
between LTE and non-LTE (ISM) radio communications in at least the
following scenarios: LTE Band 40/41 radio transmitter causing
interference to ISM radio receiver; ISM radio transmitter causing
interference to LTE Band 40/41 radio receiver; LTE Band 7 radio
transmitter causing interference to ISM radio receiver; ISM radio
transmitter causing interference to LTE Band 7 radio receiver; and
LTE Band 7/13/14 radio transmitter causing interference to GPS
radio receiver.
When such undesired interference arises as a result of
communication occurring concurrently in the same mobile device or
in the same base station (for example, as a result of concurrent
use of LTE and non-LTE radio technologies) the interference is
sometimes referred to as `in-device coexistence (IDC) interference`
which causes an `in-device coexistence (IDC) situation`.
In order to be able to alleviate the problems due to IDC
interference, the mobile device may be configured to attempt to
address such IDC problems on its own and, if the mobile device
cannot solve the problem on its own, with the assistance of its
serving base station. For example, an IDC problem may be addressed
by the base station selecting a different frequency (FDM solution)
for the mobile device, by reconfiguring its transmissions (e.g.
apply discontinuous reception (DRX) and/or change its subframe
pattern) (TDM solution), and/or by adjusting the base station's
(and/or the mobile device's) transmission power (Power Control
solution).
The inventors have realised that difficulties may arise in
simultaneously operating both the LTE and non-LTE parts of such
dual FAPs due to the potentially severe interference experienced in
some of the (neighbouring or overlapping) frequency bands used by
both the LTE and the non-LTE communication technologies.
Such difficulties are particularly likely to occur with respect to
dual FAPs implementing both an LTE base station and a non-LTE
access point as part of the same network node. In this case, the
above (FDM/TDM/Power Control) solutions are not always applicable
because any change in the operation of the LTE base station (of the
dual FAP) may still cause (or continue to cause) unexpected
interference for communications using the access point part of the
dual FAP.
The inventors have also realised that whilst it is possible to
co-ordinate some of the operations of LTE base stations and other
base stations operating in accordance with an earlier standard from
which LTE has been derived, e.g. due to the inherent backward
compatibility between such related standards, it is particularly
difficult to ensure optimal communication characteristics (e.g.
signal quality, error rate, interference level) for dual FAPs
implementing both an LTE base station and a non-LTE access point
because of the differences between the operation of the LTE and the
non-LTE parts.
SUMMARY OF INVENTION
There is therefore a need to improve the operation of the mobile
device and the dual FAP in order to overcome or at least alleviate
the above problems. Exemplary embodiments of the present invention
aim to provide improved techniques for alleviating interference
(hence improving data throughput) in a communication network and,
in particular, for alleviating radio interference caused to, or by,
transmissions via a dual FAP (and/or the like).
In one aspect, the invention provides a communication apparatus
comprising: a base station module for providing wireless
connectivity in a communication network, using a first
communication protocol, to at least one mobile communication
device; an access point module for providing wireless connectivity
in a communication network, using a second communication protocol,
to the at least one mobile communication device; and an interface
for coupling the base station module and the access point module,
wherein said interface is configured for communication between said
base station module and said access point module; wherein said base
station module and said access point module are configured for
co-operation with one another by communicating via said interface,
and wherein at least one of said base station module and said
access point module is configured to perform at least one operation
to alleviate interference arising due to coexistence, in said
communication apparatus, of said base station module and said
access point module, as part of said co-operation.
In one aspect, the invention provides a method performed by a
communication apparatus comprising: i) a base station module for
providing wireless connectivity, using a first communication
protocol, in a communication network to at least one mobile
communication device; ii) an access point module for providing
wireless connectivity, using a second communication protocol, in a
communication network to the at least one mobile communication
device; and iii) an interface for coupling the base station module
and the access point module, wherein said interface is configured
for communication between said base station module and said access
point module; the method comprising: the base station module and
the access point module co-operating with one another by
communicating via said interface, and at least one of said base
station module and said access point module performing at least one
operation to alleviate interference arising due to the coexistence,
in said communication apparatus, of said base station module and
said access point module, as part of said co-operating.
In one aspect, the invention provides a system for use in a
telecommunication network, comprising one or more mobile
communication devices and the above described communication
apparatus.
Aspects of the invention extend to computer program products such
as computer readable storage media having instructions stored
thereon which are operable to program a programmable processor to
carry out a method as described in the aspects and possibilities
set out above or recited in the claims and/or to program a suitably
adapted computer to provide the apparatus recited in any of the
claims.
BRIEF DESCRIPTION OF DRAWINGS
Exemplary embodiments of the invention will now be described, by
way of example, with reference to the accompanying drawings in
which:
FIG. 1 schematically illustrates a mobile telecommunication system
of a type to which the invention is applicable;
FIG. 2 schematically illustrates the relationship between some of
the entities forming part of the mobile telecommunication system of
FIG. 1;
FIG. 3 schematically illustrates various radio transceiver circuits
implemented on a mobile device of the mobile telecommunication
system shown in FIG. 1;
FIG. 4 schematically illustrates various radio transceiver circuits
implemented on the base station of the mobile telecommunication
system shown in FIG. 1;
FIG. 5 is a block diagram of a mobile device forming part of the
mobile telecommunication system shown in FIG. 1;
FIG. 6 is a block diagram of the home base station forming part of
the mobile telecommunication system shown in FIG. 1;
FIG. 7 is a block diagram of the access point forming part of the
mobile telecommunication system shown in FIG. 1;
FIGS. 8a to 11 are exemplary timing diagrams illustrating various
methods performed by the nodes forming part of the mobile
telecommunication system shown in FIG. 1; and
FIG. 12 illustrates some of the frequency bands and channels that
may be affected by interference arising from the coexistence of LTE
and non-LTE technologies in the same base station.
DESCRIPTION OF EMBODIMENTS
Overview
FIG. 1 schematically illustrates a mobile (cellular)
telecommunication system 1 in which users of mobile devices 3 (for
example mobile telephones 3-1 to 3-3) can communicate with other
users via one or more base stations 5 and a core network 7. In the
system illustrated in FIG. 1, the base station 5 is a dual mode
base station (dual FAP) which comprises an LTE home base station
(HeNB) part 5-1 (e.g. a pico/femto base station or other low-power
node) and a non-LTE access point (AP) part 5-2 (e.g. a Wi-Fi AP).
In this example, the HeNB part 5-1 and the AP part 5-2 are
co-located (and hence they share at least some hardware and/or
software components), although the HeNB part 5-1 and the AP part
5-2 may also be implemented as two physically separate units. An
appropriate dedicated interface (e.g. an internal interface or an
external one) is provided for communications between the HeNB part
5-1 and the AP part 5-2. Further details about the relationship
(and communication links provided) between the HeNB part 5-1 and
the AP part 5-2 and various associated network nodes are
illustrated in FIG. 2.
Both the HeNB part 5-1 and the AP part 5-2 operate at least one
cell (not shown), each cell having a number of uplink (UL) and
downlink (DL) communication resources (channels, sub-carriers, time
slots, etc.) that are available for wireless communications between
the mobile devices 3 and the dual FAP 5 (i.e. the HeNB part 5-1
and/or the AP part 5-2). In this example, the Radio Access
Technologies (RATs) employed by the dual FAP 5 operate according to
either Frequency Division Duplexing (FDD) or Time Division
Duplexing (TDD). In TDD, the time domain of a communication channel
is divided into several recurrent time slots of fixed length in
which communication to/from the dual FAP 5 can be scheduled. In
operation in TDD, two or more data streams may be transferred
between the dual FAP 5 (e.g. HeNB part 5-1) and the mobile
device(s) 3, apparently simultaneously, in sub-channels of one
communication channel, by scheduling each data stream in different
time slots of the channel (effectively `taking turns`). In FDD, the
bandwidth available to the base station is divided into a series of
non-overlapping frequency sub-bands each comprising frequency
resources that may be assigned to mobile device(s) 3 for
communication via the dual FAP 5.
In this example, the first mobile device 3-1 is connected to both
the HeNB part 5-1 and the AP part 5-2, whilst the second mobile
device 3-2 is connected to the HeNB part 5-1 only, and the third
mobile device 3-3 is connected to the AP part 5-2 only. Whilst this
particular arrangement is shown in FIG. 1 for purely illustrative
purposes, it will be appreciated that compatible mobile devices 3
may connect to either one or both of the HeNB part 5-1 and the AP
part 5-2 (and/or to any further base station) depending on their
capabilities, applicable configurations, and/or network conditions
that are outside the scope of the present invention.
As can be seen, at least the mobile devices 3-1 and 3-3 are capable
of communicating using non-LTE radio technologies such as those
which use resources of the Industrial, Scientific and Medical (ISM)
frequency bands. In this example, the mobile devices 3-1 and 3-3
can communicate with the AP part 5-2 of the dial FAP 5 operating
according to one of the 802.11 family of standards (Wi-Fi) defined
by the Institute of Electrical and Electronics Engineers (IEEE).
Although not shown in FIG. 1, each of the mobile devices 3 may also
be able to communicate with other non-LTE transceivers, e.g. with a
wireless headset operating according to the Bluetooth standard
defined by the Bluetooth Special Interest Group (SIG) and/or
support positioning technologies and thus communicate with, for
example, a positioning satellite using GPS signals.
Communications between the mobile device(s) 3 and the AP part 5-2
(and possibly between the mobile devices 3 and other non-LTE
transceivers) might occur substantially concurrently with the
communications between the mobile device(s) 3 and the HeNB part
5-1, which concurrent communications have the potential to cause
undesirable interference (i.e. IDC interference).
The issue of IDC interference is illustrated further in FIG. 3
which schematically illustrates, purely illustratively, the various
radio transceiver circuits implemented on a mobile device 3 shown
in FIG. 1. Further, FIG. 4 schematically illustrates, purely
illustratively, the various radio transceiver circuits implemented
on the dual FAP 5 shown in FIG. 1. As shown in FIG. 3, the mobile
device (e.g. mobile device 3-1) comprises an LTE baseband circuit
30a, a GPS baseband circuit 30b, and an ISM baseband circuit 30c.
Each baseband circuit 30a to 30c is coupled to a radio frequency
(RF) transceiver (or receiver), i.e. LTE RF transceiver 31a, GPS RF
transceiver 31b, and ISM RF transceiver 31c, respectively.
Communications in the LTE band are carried out using an LTE antenna
33a. Similarly, communications in the non-LTE bands are carried out
using the respective GPS antenna 33b and/or the ISM antenna
33c.
As indicated by dashed arrows in FIG. 3, any of the transceivers
31a to 31c might suffer interference from either one of the other
transceivers operating in the same mobile device 3. Similarly, as
indicated by dashed arrow in FIG. 4, the transceivers 51-1 and 51-2
of the base station 5 might also suffer interference from each
other (and/or from the transceivers 31a to 31c of the mobile device
3).
Returning to FIG. 1, the dual FAP 5 is beneficially configured to
alleviate any such in-device coexistence (IDC) interference.
Specifically, the HeNB part 5-1 and the AP part 5-2 are configured
to co-ordinate their operations, e.g. by exchanging information
using the dedicated interface 100 provided therebetween (e.g. an
interface provided directly between the HeNB part 5-1 and the AP
part 5-2 and/or using an external connection, such as a connection
provided via one or more gateways and/or the core network 7).
In particular, the HeNB part 5-1 and the AP part 5-2 are configured
to interact with each other for the alleviation of an
(ongoing/potential) IDC interference by exchanging information
relating to one or more of the following functionalities:
interference management; power control; carrier frequency
re-selection; energy saving; radio transmission state (e.g.
on/off); and load balancing.
For example, by exchanging some of the above information, the dual
FAP 5 is beneficially able to alleviate an IDC interference in LTE
Band 40 (which may be caused by transmissions, in the lower portion
of the ISM band, to LTE Band 40, or vice versa). In this case, one
or more of the following solutions may be applied by the dual FAP
5: i) the HeNB part 5-1 may request the AP part 5-2 not to use one
or more channels close to the lower portion of the ISM band (e.g.
ISM Channels 1 to 3), i.e. to select other channels if possible;
ii) the HeNB part 5-1 may restrict (avoid) scheduling the PRBs in
the higher portion of LTE Band 40 in both uplink and downlink (i.e.
in a region close to ISM Channel 1) when the coexisting Wi-Fi
devices, such as the AP part 5-2 and a Wi-Fi capable mobile device
3, use one or more ISM channels close to LTE Band 40; and iii) the
HeNB part 5-1 may impose power restrictions (for LTE
communications) while scheduling the PRBs in the higher portion of
LTE Band 40 in both uplink and downlink (i.e. in a region close to
ISM Channel 1) if it is found necessary to use these PRBs (e.g. if
solution ii) is not or cannot be employed).
Similarly to the above, the dual FAP 5 is also beneficially able to
alleviate an IDC interference in LTE Band 7 (which may be caused by
transmissions, in ISM Channel 14, to LTE Band 7, or vice versa,
since there is only a 5 MHz separation between the uplink portion
of LTE Band 7 and Wi-Fi Channel 14, and almost half of Wi-Fi
Channel 14 lies within the LTE guard band). In this case, one or
more of the following possible solutions may be applied by the dual
FAP 5: iv) the HeNB part 5-1 may request the AP part 5-2 not to use
one or more channels close to the higher portion of the ISM band
(e.g. ISM Channels 12 to 14), i.e. to select other channels if
possible; v) the HeNB part 5-1 may restrict (avoid) scheduling the
PRBs in the lower portion of LTE Band 7 in uplink (i.e. in a region
close to ISM Channel 14) when the coexisting Wi-Fi devices (such as
the AP part 5-2 and a Wi-Fi capable mobile device 3) are using one
or more channels close to LTE Band 7; and vi) the HeNB part 5-1 may
obtain timing information from the AP part 5-2, using which
information the HeNB part 5-1 may be arranged to avoid scheduling
any uplink (LTE) communications (at least in LTE Band 7) at least
for the duration of any ISM transmission by the AP part 5-2 (or the
mobile devices 3) in Wi-Fi Channel 14. It will be appreciated that
solutions iv) to vi) may also be applied to LTE Band 41 instead of
(or in addition to) LTE Band 7.
Furthermore, the HeNB part 5-1 may be configured to adjust its
maximum transmission power on the downlink (and/or to adjust the
maximum transmission power allowed for the mobile device 3 on the
uplink) in accordance with information relating to the operation of
the AP part 5-2 (e.g. channels used, transmit powers, etc.), and
thereby alleviate any interference caused by the LTE transmissions
of the HeNB part 5-1 to the AP part 5-2. Similarly, the AP part 5-2
may be advantageously configured to obtain information from the
HeNB part 5-1 relating to the currently used/permitted power (e.g.
maximum or average power) by the HeNB part 5-1 for its downlink and
uplink communications with the mobile devices 3, and to adjust its
own transmissions accordingly.
The HeNB part 5-1 may also be configured to alleviate any
interference caused by the LTE transmissions of the HeNB part 5-1
to the AP part 5-2 by initiating carrier frequency re-selection
procedures with respect to the mobile devices 3 for which LTE
communications are scheduled in LTE Bands prone to causing
interference to (or experiencing interference from) the ISM
communications. For example, the HeNB part 5-1 may be configured to
determine, based on information relating to the operation of the AP
part 5-2 (e.g. the ISM channels and/or the associated transmission
power being used), which carrier frequency needs to be re-selected
(e.g. instead of an interfering or potentially interfering carrier
frequency currently used).
Moreover, the HeNB part 5-1 and the AP part 5-2 may also be
configured to inform each other when their transceivers are
entering and/or exiting a low-power operating mode (e.g. an energy
saving mode) during which transmissions over one or more (e.g. all)
frequency bands are suspended. Using the exchanged information
relating to the current power state of the HeNB part 5-1 and/or the
AP part 5-2, the dual FAP 5 is beneficially able to alleviate a
potential interference by restricting/allowing the use of certain
frequency bands/channels in dependence on the current operating
mode of the HeNB part 5-1 and/or the AP part 5-2. For example, the
AP part 5-2 may restrict usage of certain ISM channels whilst the
HeNB part 5-1 is operating at normal power (i.e. whilst the HeNB
part is not in a power saving mode) and allow usage of such ISM
channels whilst the HeNB part 5-1 is operating in a power saving
mode (and this has been informed by the HeNB part 5-1).
The HeNB part 5-1 and the AP part 5-2 may also be configured to
perform load balancing (e.g. by steering traffic between the HeNB
part 5-1 and the AP part 5-2) based on the information exchanged
between them. In this case, the exchanged information may relate to
the number of mobile devices 3 served by the HeNB part 5-1 and the
AP part 5-2, respectively and/or the associated load (or remaining
capacity) thereof.
In summary, any of the above approaches may beneficially contribute
to the alleviation (e.g. reduction, prevention) of interference
arising due to the co-location of the HeNB part 5-1 and the AP part
5-2 in the dual FAP 5 (and/or the like). This in turn may increase
the overall data throughput that can be achieved by the dual FAP 5
compared to other dual mode base stations that do not support the
above features.
Mobile Device
FIG. 5 is a block diagram of a mobile device 3 forming part of the
mobile telecommunication system 1 shown in FIG. 1. As shown, the
mobile device 3 includes transceiver circuits 31a to 31c which are
operable to transmit signals to and to receive signals from the
base station 5 via one or more antennas 33a to 33c. Although not
necessarily shown in FIG. 5, the mobile device 3 may of course have
all the usual functionality of a conventional mobile telephone
(such as a user interface 35) and this may be provided by any one
or any combination of hardware, software and firmware, as
appropriate. The mobile device 3 has a controller 37 to control the
operation of the mobile device 3. The controller 37 is associated
with a memory 39 and is coupled to the transceiver circuits 31a to
31c. The controller 37 controls the operation of the transceiver
circuits 31a to 31c in accordance with software and data stored in
memory 39.
Software may be pre-installed in the memory 39 and/or may be
downloaded via the telecommunications network or from a removable
data storage device (RMD), for example. The software includes,
among other things, an operating system 41, an LTE module 43, an
ISM module 45, a GPS module 47 (optional), a measurement and
reporting module 48, and a traffic steering module 49.
The LTE module 43 controls the communications of the mobile device
3 using the LTE radio technologies. The LTE module 43 receives
instructions from the base station 5 (via the LTE transceiver
circuit 31a and the LTE antenna 33a) and stores them in the memory
39. Based on the received instructions, the LTE module 43 is
operable to select the appropriate frequency band, transmission
power, modulation mode etc. used in the LTE communications. The LTE
module 43 is also operable to update the base station 5 about the
amount and type of uplink and/or downlink data scheduled for
transmission in order to assist the base station 5 in allocating
resources among the mobile devices it is serving.
The ISM module 45 controls the ISM (e.g. IEEE 802.11)
communications of the mobile device 3. In doing so, the ISM module
45 might, for example, use data received from the access point part
5-2 and/or communicate with a wireless headset and/or the like.
If present, the GPS module 47 is operable to obtain a current
geographic location of the mobile device 3 and to control the GPS
communications of the mobile device 3. In doing so, the GPS module
47 might, for example, use data received from a positioning
satellite.
The measurement and reporting module 48 is responsible for
performing signal measurements (including interference
measurements) and to generate and send (via the LTE transceiver
31a) a measurement report to the HeNB part 5-1. In order to do so,
the measurement and reporting module 48 is operable to obtain a
measurement configuration from the HeNB part 5-1. The measurement
and reporting module 48 may also be operable to indicate the
occurrence of in-device interference by sending an associated IDC
indication to the HeNB part 5-1 via the LTE transceiver 31a. In
this embodiment the measurement and reporting module 48 and the
HeNB part 5-1 communicates using one or more dedicated radio
resource control (RRC) message although any appropriate signalling
may be used.
The traffic steering module 49 is responsible for steering traffic
between the HeNB part 5-1 and the AP part 5-2, as instructed by the
dual FAP 5. In order to do so, the traffic steering module 49 is
operable to receive and process a steering command from the HeNB
part 5-1. Such steering command may be received, for example,
subsequent to (e.g. in response to) the measurement and reporting
module 48 sending a measurement report to the HeNB part 5-1.
LTE Base Station
FIG. 6 is a block diagram of the HeNB part 5-1 of the dual FAP 5
forming part of the mobile telecommunication system 1 shown in FIG.
1. As shown, the HeNB part 5-1 includes a transceiver circuit 51-1
which is operable to transmit signals to and to receive signals
from the mobile devices 3 via one or more antennas 53-1 and to
transmit signals to and receive signals from the core network 7 and
other base stations via the network interface 55 (which may be a
copper or optical fibre interface). A controller 57 controls the
operation of the transceiver circuit 51-1 in accordance with
software and data stored in memory 59. The software includes, among
other things, an operating system 61, an LTE communication control
module 63, a radio resource control (RRC) module 65, and an ISM
interface module 67 (which includes a load balancing module 70, a
channel control module 71, and a power control module 72).
The communication control module 63 controls communications between
the HeNB part 5-1 (i.e. the LTE base station part of the dual FAP
5) and external devices (such as the mobile devices 3) via the
transceiver circuit 51-1 and the one or more antenna 53-1. The
communication control module 63 also controls communications
between the HeNB part 5-1 and core network nodes (such as the MME
12, the S-GW 14, and/or the P-GW 16) via the transceiver circuit
51-1 and the network interface 55 (which may comprise e.g. an S1
interface).
The RRC module 65 manages (generates, sends, and receives) messages
formatted in accordance with the RRC protocol. For example, the RRC
module 65 is operable to communicate RRC messages with the mobile
devices 3 (e.g. RRC messages relating to signal measurements).
The ISM interface module 67 controls communication with the AP part
5-2 (with the corresponding LTE interface module 69 thereof) over
the dedicated interface 100 provided between the HeNB part 5-1 and
the AP part 5-2. For example, the ISM interface module 67 is
operable to exchange information with the AP part 5-2 in order to
assist the alleviation of interference resulting from the
simultaneous use of both the LTE and the non-LTE (ISM)
communication technologies. Specifically, the ISM interface module
67 includes the load balancing module 70, which is responsible for
performing load balancing based in information exchanged with the
AP part 5-2. The ISM interface module 67 also includes the channel
control module 71, which is responsible for performing channel
control based in information exchanged with the AP part 5-2. In
this example, the ISM interface module 67 further includes the
power control module 72, which is responsible for performing power
control (based in information exchanged with the AP part 5-2). It
will be appreciated that the ISM interface module 67 may include a
number of additional modules and/or that any of the modules 70 to
72 (and/or any such additional modules) may be combined, if
appropriate.
Access Point
FIG. 7 is a block diagram of the access point part 5-2 of the dual
FAP 5 forming part of the mobile telecommunication system 1 shown
in FIG. 1. As shown, the access point part 5-2 includes a
transceiver circuit 51-2 which is operable to transmit signals to
and to receive signals from the mobile devices 3 via one or more
antennas 53-2 and to transmit signals to and receive signals from
the core network 7 and other base stations 5 via the network
interface 55 (which may be a copper or optical fibre interface). A
controller 57 controls the operation of the transceiver circuit
51-2 in accordance with software and data stored in memory 59. The
software includes, among other things, an operating system 61, a
non-LTE (e.g. ISM) communication control module 64, and an LTE
interface module 69 (which includes a load balancing module 70, a
channel control module 71, and a power control module 72)
The communication control module 64 controls communications between
the access point part 5-2 and external devices (such as the mobile
devices 3) via the transceiver circuit 51-2 and the one or more
antenna 53-2. The communication control module 64 also controls
communications between the AP part 5-2 and other network nodes
(either directly or via one or more gateways) via the transceiver
circuit 51-2 and the network interface 55.
The LTE interface module 69 controls communication with the HeNB
part 5-1 (with the corresponding ISM interface module 67 thereof)
over the dedicated interface 100 provided between the HeNB part 5-1
and the AP part 5-2. For example, the LTE interface module 69 is
operable to exchange information with the HeNB part 5-1 in order to
assist the alleviation of interference resulting from the
simultaneous use of both the LTE and the non-LTE (ISM)
communication technologies. Specifically, the LTE interface module
69 includes the load balancing module 70, which is responsible for
performing load balancing based in information exchanged with the
HeNB part 5-1. The LTE interface module 69 also includes the
channel control module 71, which is responsible for performing
channel control based in information exchanged with the HeNB part
5-1. In this example, the LTE interface module 69 further includes
the power control module 72, which is responsible for performing
power control (based in information exchanged with the HeNB part
5-1). It will be appreciated that the LTE interface module 69 may
include a number of additional modules and/or that any of the
modules 70 to 72 (and/or any such additional modules) may be
combined, if appropriate.
In the above description, the mobile device 3, the home base
station 5-1, and the access point part 5-2 are described for ease
of understanding as having a number of discrete modules (such as
the communication control modules and the LTE/ISM interface
modules). Whilst these modules may be provided in this way for
certain applications, for example where an existing system has been
modified to implement the invention, in other applications, for
example in systems designed with the inventive features in mind
from the outset, these modules may be built into the overall
operating system or code and so these modules may not be
discernible as discrete entities.
Operation
Examples of methods used for alleviating interference, between the
home base station 5-1 and the access point part 5-2 of a dual FAP
5, will now be described. Although for efficiency of understanding
for those skilled in the art, the invention will be described in
detail in the context of a home base station (HeNB part) and an
access point part of a dual FAP, the principles described herein
can be applied to a `multimode` FAP comprising more than one (home)
base station and/or more than one access point part (which may each
operate according to different standards) with the corresponding
elements of the system changed as required.
First Embodiment
FIG. 8a shows an exemplary timing diagram illustrating a method
performed by the HeNB part 5-1 and the AP part 5-2 of the mobile
telecommunication system 1 shown in FIG. 1. In this example, the
HeNB part 5-1 and the AP part 5-2 are configured to apply channel
restriction, e.g. in order to alleviate (on-going or potential)
interference resulting from the simultaneous use of both the LTE
and the non-LTE (ISM) communication technologies.
As mentioned above, the HeNB part 5-1 and the AP part 5-2 are
configured to alleviate any IDC interference (ongoing and/or
potential) by exchanging information (either within the dual FAP 5
or using an external connection, such as a connection provided via
one or more gateways and/or the core network 7).
In this example, the HeNB part 5-1 requests the AP part 5-2 not to
use one or more channels close to the lower portion of the ISM band
(e.g. ISM Channels 1 to 3). In order to do so, the HeNB part 5-1
generates (using its ISM interface module 67/channel control module
71) and sends, in step S801, an appropriately formatted message
(e.g. a `Restrict Channel Request` message) to the AP part 5-2,
requesting the AP part 5-2 to apply channel restriction with
respect to one or more ISM channels. The HeNB part 5-1 also
includes in the message sent at S801 information identifying the
channels to be restricted (e.g. a channel ID associated with the
ISM channel and/or a band ID associated with the interfering LTE
band).
In response to the HeNB's 5-1 request, the AP part 5-2 determines
(using its channel control module 71) whether or not it is able to
apply the requested restriction. If the AP part 5-2 determines that
it is able to proceed with the HeNB's 5-1 request, it begins to
apply (in step S803) the channel restriction (using its channel
control module 71) with respect to the ISM channel(s) identified in
the request received at S801. Such a channel restriction may be
maintained by the AP part 5-2 at least until receiving a further
message from the HeNB part 5-1 lifting the restriction and/or until
the expiry of an associated `channel restriction` timer (which may
be set to e.g. a default timer value and/or a timer value
configured by the message at S801).
Once the AP part 5-2 has complied with the requested channel
restriction, it generates (using its LTE interface module 69) and
sends, in step S805a, an appropriate signalling message (e.g. a
`Restrict Channel Acknowledgement` message) informing the HeNB part
5-1 that the restriction is in place. Advantageously, the HeNB part
5-1 is able to communicate with the mobile devices 3 using the LTE
channels neighbouring or overlapping with the ISM channel(s)
operated by the AP part 5-2 without causing unnecessary
interference to these communications.
It will be appreciated that any communications already allocated to
the restricted ISM channel(s) may be either terminated or moved
(handed over, steered, etc.) to a different (i.e. non-restricted)
channel.
In this embodiment, the HeNB part 5-1 may use, for example, LTE
frequency Band 40 and it may request the AP part 5-2 to restrict
usage of at least one of ISM Channels 1 to 3. The HeNB part 5-1 may
also use LTE frequency Band 7 (and/or LTE Band 41), in which case
it may request the AP part 5-2 to restrict usage of at least one of
ISM Channels 12 to 14.
Second Embodiment
FIG. 8b shows a modification of the method shown in FIG. 8a. In
this case, the AP part 5-2 is unable to comply with the requested
channel restriction and the HeNB part 5-1 is configured to
alleviate interference on its own.
Step S801 of FIG. 8b is identical to step S801 of FIG. 8a. However,
in this case the AP part 5-2 (using its channel control module 71)
determines that the requested channel restriction cannot be
applied. This may happen, for example, when such restriction is
already in place, the channel to be restricted is not supported by
the AP part 5-2, the channel is used by communications that cannot
be interrupted/moved to other channels, and/or the like.
As shown generally in step S803, the AP part 5-2 does not apply the
requested channel restriction. Instead, the AP part 5-2 generates
(using its LTE interface module 69) and sends, in step S805b, an
appropriate signalling message (e.g. a `Restrict Channel Negative
Acknowledgement (Nack)` message) informing the HeNB part 5-1 that
the requested restriction cannot be complied with (at least with
respect to some of the channel identified in the message at
S801).
Advantageously, in this case the HeNB part 5-1 is able to apply a
scheduling restriction (using its channel control module 71) and/or
apply power control (using its power control module 72) to its own
communications (e.g. with the mobile device 3-1) over the affected
LTE Band. Thus, for example, if the AP part 5-2 is unable to
restrict usage of at least one of ISM Channels 1 to 3, the HeNB
part 5-1 may restrict usage of its own LTE frequency Band 40 (in
downlink, uplink, or both). If the AP part 5-2 is unable to
restrict usage of at least one of ISM Channels 12 to 14, the HeNB
part 5-1 may restrict usage of its own LTE frequency Band 7 (and/or
Band 41), in downlink and/or uplink.
The HeNB part 5-1 is thus able to communicate with the mobile
devices 3 without causing unnecessary interference to these
communications using appropriate LTE bands (i.e. non-restricted
bands) even if the AP part 5-2 cannot or does not comply with the
requested restriction.
Third Embodiment
FIG. 9a shows another modification of the method shown in FIG. 8a.
Similarly to FIG. 8b, in this case the AP part 5-2 is unable to
comply with the requested channel restriction and the HeNB part 5-1
is configured to alleviate interference on its own.
Steps S901 to S905a correspond to steps S801 to S805b of FIG. 8b,
respectively, hence their description will not be repeated
here.
In this case however, as shown in step S907, the HeNB part 5-1
(using its channel control module 71) applies a scheduling
restriction and/or intelligent uplink scheduling to its own
communications (e.g. with the mobile device 3-1) over the affected
LTE Band(s). This may be particularly beneficial in case of LTE
Band 7 in the uplink in case the AP part 5-2 is unable to restrict
usage of at least one of ISM Channels 12 to 14. However, it will be
appreciated that this modification may also be applied to downlink
communications in LTE Band 7 and/or communications in other bands,
e.g. LTE Bands 40/41, as described above.
Additionally, the HeNB part 5-1 may also be configured to obtain
from the AP part 5-2 (e.g. in step S905a or in a separate step)
information identifying a frame timing applied by the AP part 5-2,
i.e. information identifying the transmission pattern (if any)
and/or duration used by the AP part 5-2 over the interfering
channel. Beneficially, the HeNB part 5-1 is able to apply
intelligent uplink scheduling for the affected LTE Band(s) using
the obtained frame timing information, e.g. by avoiding scheduling
UL transmissions in the affected LTE band(s) (e.g. Band 7/41) for
the duration of the AP's 5-2 transmissions in the interfering ISM
Channel(s) (e.g. Channel 12/13/14).
Fourth Embodiment
FIG. 9b shows an exemplary timing diagram illustrating a method
performed by the HeNB part 5-1 and the AP part 5-2 of the mobile
telecommunication system 1 shown in FIG. 1. In this example, the
HeNB part 5-1 is configured to control its maximum transmit power
based on information obtained from the AP part 5-2.
Initially, as generally shown in step S910, the HeNB part 5-1
receives the applicable maximum transmission (`Tx`) power value
from the Home eNodeB Management System (HeMS). The HeNB part 5-1 is
configured to adjust, based on information obtained from the AP
part 5-2, its maximum transmission power, thereby reducing (as much
as possible) the amount of interference to the coexisting AP part
5-2.
Specifically, in this example the AP part 5-2 (using its power
control module 72) generates and sends, in step S911, an
appropriately formatted message (e.g. a `Channel/Transmit Power
Information Request` message) to the HeNB part 5-1, e.g. over the
dedicated interface 100. The AP part 5-2 includes in this message
information identifying one or more channel (e.g. at least one of
ISM Channels 1 to 3, and 12 to 14) used by the AP part 5-2 in its
communications with the mobile devices 3, and a respective
associated transmit power used in the identified one or more
channel.
Next, in step S913, the HeNB part 5-1 configures its power control
module 72 to apply an appropriate UL/DL maximum transmit power,
which also takes into account the received information identifying
the one or more channel used by the AP part 5-2 and the respective
associated transmit power.
Specifically, the HeNB part 5-1 is configured to adjust the value
of the so-called `Pmax` parameter (which determines the HeNB's 5-1
maximum transmission power) based on an offset that is dependent on
the channel information and/or power used by AP part 5-2. Further,
the HeNB part 5-1 is configured to adjust/set the maximum allowed
UL transmit power of the mobile devices 3 within the cell operated
by the HeNB part 5-1, also based on the received information
identifying the one or more channel used by the AP part 5-2 and the
respective associated transmit power. It will be appreciated that
in determining an appropriate UL/DL maximum transmit power the HeNB
part 5-1 may be configured to take into account other information
as well, for example, information relating to network monitor mode
(NMM) measurements (also referred to as Network Listen Mode (NLM)
measurements).
Once the HeNB part 5-1 has successfully configured its power
control module 72 with the appropriate UL/DL maximum transmit
powers, it generates (using its ISM interface module 67) and sends,
in step S915, an appropriate signalling message (e.g. a
`Channel/Transmit Power Information Acknowledgement` message) to
the AP part 5-2.
Beneficially, by applying an appropriate transmit power setting (to
the HeNB's 5-1 transmissions) that also take into account the
information identifying the AP's 5-2 channel(s) and associated
transmit power(s), the HeNB part 5-1 is able to alleviate (on-going
or potential) interference resulting from the simultaneous use of
both the LTE and the non-LTE (ISM) communication technologies in
the dual FAP 5.
Fifth Embodiment
FIGS. 10a and 10b show exemplary timing diagrams illustrating a
method performed by the HeNB part 5-1 and the AP part 5-2 of the
mobile telecommunication system 1 shown in FIG. 1. In this example,
the HeNB part 5-1 is configured to control the AP's 5-2 band
restriction based on the current operating state of the HeNB part
5-1.
The procedure begins in step S1000, in which the HeNB part 5-1
enters an energy saving mode (ESM), e.g. during which transmissions
over one or more (e.g. all) LTE frequency bands are suspended. In
response to this change of operating mode, the HeNB part 5-1 (using
its ISM interface module 67) generates and sends, in step S1001, an
appropriately formatted message (over the dedicated interface 100)
informing the AP part 5-2 about the activation of the energy saving
mode. The HeNB part 5-1 may also include in this message
information identifying the LTE Bands in which its transmissions
are suspended (e.g. if not all LTE Bands are suspended) and/or for
which the ESM is applicable.
In response to this message, as shown in step S1003, the AP part
5-2 (using its channel control module 71 and/or power control
module 72) discontinues the enforcement of any restriction that has
been applied to its ISM transmissions (e.g. in any of Channels 1 to
3, and 12 to 14). The AP part 5-2 (using its LTE interface module
69) generates and sends, in step S1005, an appropriately formatted
message (e.g. an `Entering ESM Response` message) to the HeNB
confirming that the ISM band restrictions have been lifted.
FIG. 10b illustrates the reverse of this procedure, in which the
HeNB part 5-1 exits the energy saving mode of operation and
notifies the AP part 5-2 to start applying one or more restrictions
to its ISM communications thereby alleviating a potential
interference arising due to the concurrent use the LTE and non-LTE
technologies.
As shown in step S1010, this procedure begins when the HeNB part
5-1 exits the energy saving mode of operation (e.g. the ESM mode
described above). In response to this change of operating mode, the
HeNB part 5-1 (using its ISM interface module 67) generates and
sends, in step S1011, an appropriately formatted message (e.g. over
the dedicated interface 100) informing the AP part 5-2 about the
HeNB part 5-1 resuming its normal (i.e. non-ESM) mode of operation,
in which the HeNB's 5-1 transmissions over the LTE frequency bands
are no longer suspended (e.g. the de-activation of the energy
saving mode entered in step S1010). The HeNB part 5-1 may also
include in this message information identifying the LTE Bands in
which its transmissions are no longer suspended and/or LTE Bands in
which its transmissions are suspended (e.g. if some LTE Bands
remain suspended).
In response to this message, as shown in step S1013, the AP part
5-2 (using its channel control module 71 and/or power control
module 72) begins applying an enforcement of the restriction to its
ISM transmissions (e.g. in any of Channels 1 to 3, and 12 to 14).
It will be appreciated that the required restrictions may be
identified by the HeNB part 5-1 including appropriate information
in the message sent at S1011 and/or in any other suitable message
(such as the messages described above with reference to FIGS. 8a to
9b).
Next, the AP part 5-2 (using its LTE interface module 69) generates
and sends, in step S1015, an appropriately formatted message (e.g.
an `Exiting ESM Response` message) to the HeNB confirming that the
ISM band restrictions have been (re-) applied.
It will be appreciated that at this point the procedure may return
to step S1010, e.g. if the HeNB part 5-1 subsequently enters its
energy saving mode.
Thus, in summary, whenever the HeNB part 5-1 enters the energy
saving mode, it may inform the AP part 5-2 (e.g. over the dedicated
interface 100) about its current energy saving mode (and/or its
mode transition) so that the AP part 5-2 can beneficially lift any
restriction (e.g. a restriction on ISM channel usage, transmission
power, and/or scheduling) that have been imposed by the HeNB part
5-1 in order to alleviate an interference arising due to the
coexistence of the LTE and non-LTE transmissions. Similarly,
whenever the HeNB part 5-1 exits the energy saving mode, it may
inform the AP part 5-2 about its current energy saving mode (and/or
its mode transition) so that the AP part 5-2 can beneficially apply
(or re-apply, as appropriate) any requested restriction (e.g. a
restriction on ISM channel usage, ISM transmission power, and/or
ISM scheduling) in order to alleviate an interference (or potential
interference) arising from the coexistence of the LTE and non-LTE
technologies in the dual FAP 5.
It will be appreciated that, by effectively mirroring the above
described procedures, the AP part 5-2 may also be configured to
inform the HeNB part 5-1 about its current energy saving mode
(and/or energy saving mode transition), in which case the HeNB part
5-1 may apply/lift an appropriate restriction to its own
transmissions in an LTE Band affected by the AP's 5-2 ISM
transmissions, in dependence on the AP's 5-2 actual energy saving
mode.
The state transitions and the associated notifications sent between
the HeNB part 5-1 and the AP part 5-2 (in either direction) are
further illustrated in FIG. 10c.
Using the exchanged information relating to the current power state
of the HeNB part 5-1 and/or the AP part 5-2, the dual FAP 5 is
beneficially able to alleviate a potential interference by
restricting/allowing the use of certain frequency bands/channels in
dependence on the current operating mode of the HeNB part 5-1
and/or the AP part 5-2.
Sixth Embodiment
FIG. 11 shows an exemplary timing diagram illustrating a method
performed by the HeNB part 5-1 and the AP part 5-2 of the mobile
telecommunication system 1 shown in FIG. 1. In this example, the
HeNB part 5-1 is configured to control the steering of traffic
to/from the AP part 5-2 based on load information obtained from the
AP part 5-2.
It will be appreciated that in this embodiment the messages used
between the HeNB part 5-1 and the mobile device 3 (denoted `UE` in
FIG. 11) conform to the RRC protocol specified in 3GPP TS 36.331.
Specifically, the message sent at S1101 may comprise an
`RRCConnectionReconfiguration message` described in Section 5.5.1
of TS 36.331 and the message sent at S1104 corresponds to the
message described in Section 5.5.5 "Measurement reporting" of TS
36.331. Step S1102 may correspond to any of the event triggers A1
to A6, B1, and B2 described in sections 5.5.4.2 to 5.5.4.8 of TS
36.331. The contents of the above sections of TS 36.331 are
incorporated herein by reference. Further, step S1102 may comprise
an event trigger relating to a non-LTE (e.g. ISM) measurement, such
as a Wi-Fi signal strength measurement, a Wi-Fi interference
measurement, and/or the like.
In this case however, as generally illustrated in step S1100, the
HeNB part 5-1 is operable to obtain load information (e.g.
congestion status information) from the AP part 5-2. It will be
appreciated that although in FIG. 11 step S1100 is shown to take
place between steps S1104 and S1105, step S1100 may take place any
time before step S1105, e.g. prior to or after S1101. Further, it
will be appreciated that the message at step S1100 may be sent by
the AP part 5-2 in response to an associated request (not shown in
FIG. 11) received from the HeNB part 5-1 (e.g. over the dedicated
interface 100).
In any case, the HeNB part 5-1 is configured to take into account
the load information obtained from the Wi-Fi AP part 5-2 (e.g.
instead or in addition to the measurement report received at S1104)
in its decision to trigger the steering of traffic to/from the
Wi-Fi AP part 5-2. Thus, when the HeNB part (using its load
balancing module 70) determines that some or all mobile devices 3
may be steered to/from the Wi-Fi AP part 5-2, it generates (using
e.g. its RRC module 65) and sends, in step S1105, an appropriately
formatted signalling message requesting the mobile devices 3 to
steer to/from the Wi-Fi AP part 5-2 in dependence on the load (e.g.
congestion status/capacity) of the AP 5-2 part indicated by the
load information received at S1100, thereby alleviating the
(potential) interference arising from the coexistence of the LTE
and non-LTE technology in the dual FAP 5.
For example, if the load information from the AP part 5-2 indicates
that the load of the AP part 5-2 (e.g. the number of mobile devices
served in the AP's 5-2 cell and/or the amount of its capacity used)
is above a predetermined threshold, then the HeNB part 5-1
instructs the mobile device 3 to steer away from the AP part 5-2
(and to possibly use another AP part and/or to use the LTE
technology instead). However, if the load information from the AP
part 5-2 indicates that the load of the AP part 5-2 is not above
(e.g. it is below) a predetermined threshold, then the HeNB part
5-1 instructs the mobile device 3 to steer to the AP part 5-2
and/or another access point part (e.g. from the HeNB part 5-1).
As shown generally in step S1107, the mobile device 3 complies with
the HeNB's 5-1 steering command, and performs an appropriate
steering of its communications to/from the wireless local area
network (WLAN) that the AP part 5-2 belongs to. Finally, the mobile
device 3 acknowledges/confirms successful receipt of the steering
command.
In either scenario, by steering the mobile device 3 to/from the AP
part 5-2/WLAN, the dual FAP 5 is beneficially able to alleviate an
undesired interference arising from its concurrent use (the
coexistence) of the LTE and non-LTE technology.
Modifications and Alternatives
A detailed exemplary embodiment has been described above. As those
skilled in the art will appreciate, a number of modifications and
alternatives can be made to the above embodiment whilst still
benefiting from the inventions embodied therein.
Although the mechanism described here is for co-located dual mode
FAPs, it can also be extended to the FAP devices that are not co
located but e.g. in close proximity. It will be appreciated that in
this case the messages may be exchanged, for example, through a
common gateway and/or a controlling node.
In the above exemplary embodiment, a mobile telephone based
telecommunication system was described. As those skilled in the art
will appreciate, the techniques described in the present
application can be employed in other communication systems. Other
communication nodes or devices (both mobile and stationary) may
include user devices such as, for example, personal digital
assistants, smartphones, laptop computers, web browsers, etc.
In the above exemplary embodiments, a number of software modules
were described. As those skilled will appreciate, the software
modules may be provided in compiled or un-compiled form and may be
supplied to the dual FAP or to the mobile device as a signal over a
computer network, or on a recording medium. Further, the
functionality performed by part or all of this software may be
performed using one or more dedicated hardware circuits. However,
the use of software modules is preferred as it facilitates the
updating of the dual FAP (HeNB part/AP part) and the mobile device
in order to update their functionalities.
In the above exemplary embodiments, the concurrent LTE and non-LTE
communications are carried out by the same dual FAP. However,
whilst the above exemplary embodiments have particular benefit for
alleviating in device coexistence interference issues, it will be
appreciated that some aspects of the invention may be employed to
alleviate interference in situations where one base station
communicates using the LTE RAT and another but separate base
station/access point in the vicinity communicates using a non-LTE
radio technology. Further, it will be appreciated that the above
mechanisms may also be applicable to a base station operating in an
unlicensed spectrum, such as a base station (of a dual FAP)
conforming to a future release of the LTE Advanced (LTE-A) set of
standards (in addition to the LTE and/or ISM standards).
In the above exemplary embodiments, the dual FAP 5 comprises
separate LTE and ISM baseband circuits 50-1 and 50-2. Each baseband
circuit 50-1 and 50-2 is coupled to its own radio frequency
transceiver 51-1 and 51-2 and uses its dedicated antenna 53-1 and
53-2. It will be appreciated that the baseband circuits 50-1 and
50-2, the transceivers 51-1 and 51-2, and the antennas 53-1 and
53-2 might be combined in one component. Alternatively, the dual
FAP 5 might employ separate circuits and/or separate transceivers
and/or separate antennas for each type of RAT that it supports. For
example, although both Bluetooth and Wi-Fi are ISM radio access
technologies, these standards may be implemented using separate
circuits and/or separate transceivers and/or separate antennas. It
is also possible that a given RAT requires more than one antenna or
uses a separate transmitter and/or receiver part.
The exemplary embodiments have been described using Wi-Fi
transceivers as an example of a non-LTE (in this case, ISM) radio
technology. However, the mechanisms described herein can be applied
to other non-LTE radio technologies (e.g. other ISM technologies,
such as Bluetooth, NFC, etc. and/or GPS technologies).
For example, the mechanisms may be applied to the following ISM
technologies: Bluetooth devices; Cordless phones; Near field
communication (NFC) devices; Wireless computer networks, such as
HIPERLAN, Wi-Fi (IEEE 802.11); Wireless technologies based on IEEE
802.15.4, such as ZigBee, ISA100.11a, WirelessHART, and MiWi.
The mechanisms may also be applied to the following Global
Navigation Satellite System (GNSS) technologies: Global or regional
satellite navigation systems, such as GPS, GLONASS, Galileo,
Compass, Beidou, DORIS, IRNSS, and QZSS; Global or regional
Satellite Based Augmentation Systems, such as Omnistar, StarFire,
WAAS, EGNOS, MSAS, and GAGAN; Ground based augmentation systems,
such as GRAS, DGPS, CORS, and GPS reference stations operating Real
Time Kinematic (RTK) corrections.
In the above exemplary embodiment described with reference to FIG.
9b, the HeNB part is described to adjust/set its own transmit power
(DL) and the transmit power (UL) for the mobile devices in the
HeNB's cell based on information obtained from the AP part. It will
be appreciated that the HeNB part may be configured to adjust the
value of `P.sub.eMax` as described in 3GPP TS 36.331, based on an
offset that is dependent on the channel information/power used by
the Wi-Fi AP part (obtained in step S911). It will also be
appreciated that the so calculated P.sub.eMax may be used for
calculating the value of `P.sub.CMAX`, which is defined in 3GPP TS
36.101.
Further, the HeNB part may be configured to derive the power
(`P.sub.PUSCH`) used on the physical uplink shared channel (PUSCH),
e.g. using the following formula (in accordance with 3GPP TS
36.213): P.sub.PUSCH(i)=min{P.sub.CMAX,10
log.sub.10(M.sub.PUSCH(i))+P.sub.O_PUSCH(j)+.alpha.(j)PL+.DELTA..sub.TF(i-
)+f(i)}
The HeNB part may also be configured to derive the power
(`P.sub.PUSCH`) used on the physical uplink control channel
(PUCCH), e.g. using the following formula (in accordance with 3GPP
TS 36.213):
.function..times..function..times..times..times..function..DELTA..times..-
times..function..DELTA..function..function. ##EQU00001##
However, it will be appreciated that, irrespective of whether or
not the AP part has provided its channel information/transmit power
information to the HeNB part, the HeNB part may be configured to
autonomously perform power control/adjustment, i.e. without taking
into account any information received from the Wi-Fi AP part. This
may be the case, for example, if LTE service is prioritized over
Wi-Fi service. It will be appreciated that the HeNB part may
perform power control purely based on NMM measurements/UE
reports.
In the above exemplary embodiments described with reference to
FIGS. 8a to 9a, and 10a to 11, the HeNB part is described to
initiate procedures by sending an appropriately formatted message
to the AP part (e.g. a restrict channel request, a power info
request, entering/exiting ESM notifications, etc.) or to the mobile
device (e.g. a steering command). However, it will also be
appreciated that similar actions may also be triggered by the AP
part (instead of the HeNB part) by the AP part sending an
appropriately formatted message to the HeNB part (or the mobile
device).
It will be appreciated that if the HeNB's current frequency is
experiencing an IDC interference (and assuming that the HeNB part
is able to use a different frequency), then the HeNB part may be
configured to perform a so-called carrier frequency reselection
procedure. Carrier frequency reselection may be required if
excessive interference is experienced by the HeNB part either due
to co-existing transmissions by the AP part and/or neighbouring
HeNB parts/Wi-Fi AP parts. In this case, the HeNB part may be
configured to perform an appropriate NMM operation and use any
information received from the AP part (e.g. over the internal
interface) about the AP's channels and the associated transmission
powers in order the HeNB part to be able to assess the interference
situation and evaluate which carrier frequency it needs to
reselect. Additionally, on changing (reselecting) the carrier
frequency, the HeNB part may be configured to inform the
co-existing Wi-Fi AP part about its newly selected operating
frequency so that any restriction can be lifted by the AP part if
the new HeNB part operating frequency is away from the lower
portion of FDD band 7, the upper portion of TDD Band 40, and/or the
lower portion of Band 41.
In the above exemplary embodiment described with reference to FIGS.
10a and 10b, the HeNB part is described to control the AP's
restrictions to use certain parts of the ISM band by sending an
appropriate notification about its current energy saving state
(i.e. whether or not its LTE transmissions are suspended). In a
modification of this exemplary embodiment, it will be appreciated
that the HeNB part may also notify the co-located AP part whether
or not its LTE radio transmissions are turned off (instead of being
suspended). For example, the HeNB part may be required to turn off
its LTE transceiver in response to a command (e.g. a `Radio
Transmission OFF` command) received from an HeMS entity and/or the
like. The HeNB part may also be required to turn off its LTE
transceiver (e.g. automatically or upon user action) in case of an
HeNB failure and/or an HeNB location change. It will be appreciated
that in such cases the procedures described with reference to FIGS.
10a and 10b may be adapted to inform the AP part about the turning
off and a subsequent turning on of the HeNB's LTE transceiver,
similarly to the indications sent upon the HeNB part
entering/exiting the energy saving mode.
In the above exemplary embodiments, the interference issues have
been described with respect to one device (e.g. dual FAP) operating
both the LTE and the non-LTE transceivers. However, it will be
appreciated that the exemplary embodiments are applicable to
interference issues involving multiple devices, e.g. one device
operating an LTE transceiver and another device operating an ISM
transceiver. The exemplary embodiments are also applicable to dual
FAPs which do not have any ongoing LTE transmissions (but e.g.
their ISM transmissions suffer from interference by another
device).
The at least one operation to alleviate interference may comprise
at least one of: an operation to restrict a channel operated by at
least one of said base station module and said access point module;
an operation to restrict a transmit power usable by at least one of
said base station module and said access point module; an operation
to schedule communications via at least one of said base station
module and said access point module; an operation to reselect a
carrier frequency used by at least one of said base station module
and said access point module; and an operation to steer traffic
to/from at least one of said base station module and said access
point module.
In one possibility, the co-operation to alleviate interference may
comprise one of said base station and said access point modules
sending a request, via said interface, for the other of said base
station and said access point modules to restrict a channel
operated by the other one of said base station and said access
point modules.
In one possibility, when said other of said base station and said
access point modules restricts said channel, in accordance with
said request, said at least one operation to alleviate interference
may comprise said other of said base station and said access point
modules restricting communications via said channel in response to
said request.
In one possibility, one of said base station and said access point
modules may be configured: i) for entering an energy saving mode in
which transmission in at least one channel is suspended; and ii)
when in said energy saving mode, for leaving said energy saving
mode and to resume said transmission in said at least one channel.
In this case, the other of said base station and said access point
modules may be configured: i) when said one of said base station
and access point modules enters said energy saving mode, to lift a
communication restriction with respect to said at least one
channel; and ii) when said one of said base station and access
point modules leaves said energy saving mode, to perform at least
one operation, to alleviate interference, comprising imposing or
re-imposing a communication restriction with respect to said at
least one channel.
In one possibility, when said other of said base station and said
access point modules does not restrict said channel, in accordance
with said request, it may send as part of said co-operation, via
said interface, a response to said request. In this case, said one
of said base station and said access point modules may be
configured to perform, based on said response, an operation, to
alleviate interference, comprising restricting communications via
at least one channel operated by said one of said base station and
said access point modules.
In one possibility, the other of said base station and said access
point module may be configured to, when said other of said base
station and said access point modules does not restrict said
channel, in accordance with said request, send as part of said
co-operation, via said interface, a response to said request; and
said one of said base station and said access point modules may be
configured to perform, based on said response, an operation, to
alleviate interference, comprising restricting a transmit power of
said one of said base station and said access point modules.
In one possibility, said other of said base station and said access
point module may be configured to, when said other of said base
station and said access point modules does not restrict said
channel, in accordance with said request, send as part of said
co-operation, via said interface, a response to said request; and
said one of said base station and said access point modules may be
configured to perform, based on said response, an operation, to
alleviate interference, comprising scheduling communications via
said one of said base station and said access point modules to
avoid said interference.
In one possibility, the co-operation may comprise said base station
module obtaining, via said interface, information identifying a
load level of said access point module, and said at least one
operation to alleviate interference may comprise at least one
operation based on said information identifying a load level of
said access point module. In this case, the at least one operation
to alleviate interference may comprise steering communication
traffic to/from at least one of said base station module and said
access point module based on said information identifying a load
level of said access point module.
In one possibility, the co-operation may comprise said base station
module obtaining, via said interface, information identifying at
least one channel operated by said access point module, and said at
least one operation to alleviate interference may comprise at least
one operation based on said information identifying at least one
channel operated by said access point module. In this case, the at
least one operation based on said information identifying at least
one channel may comprise reselecting a carrier frequency used by
said base station module based on said information identifying at
least one channel operated by said access point module whereby to
alleviate interference.
In one possibility, the co-operation may comprise said base station
module obtaining, via said interface, information identifying a
transmission power associated with at least one channel operated by
said access point module, and said at least one operation to
alleviate interference may comprise at least one operation based on
said information identifying a transmission power. In this case,
the at least one operation based on said information identifying a
transmission power may comprise reselecting a carrier frequency
used by said base station module based on said information
identifying a transmission power. In one possibility, the at least
one operation to alleviate interference may comprise applying at
least one modified transmission power level for communications
between said base station module and said one or more mobile
communication devices based on said information identifying a
transmission power.
The base station module and the access point module may be mounted
within a common housing. The communication apparatus may comprise a
dual mode femto access point. The base station module may comprise
a home base station operating in accordance with the long term
evolution (LTE) family of standards. The access point module may
comprise an access point operating in accordance with the 802.11
family of standards by the Institute of Electrical and Electronics
Engineers (IEEE).
Various other modifications will be apparent to those skilled in
the art and will not be described in further detail here.
Glossary of 3Gpp Terms
AP Access Point BT Bluetooth DRX Discontinuous Reception eNB
Evolved NodeB-base station E-UTRA Evolved UMTS Terrestrial Radio
Access E-UTRAN Evolved UMTS Terrestrial Radio Access Network FAP
Femto Access Point FDM Frequency Division Multiplexing GNSS Global
Navigation Satellite System GPS Global Positioning System GW
Gateway HeMS Home eNodeB Management System HeNB home base station
IDC In Device Coexistence ISM Industrial, Scientific and Medical
(radio bands) LTE Long Term Evolution (of UTRAN) MME Mobility
Management Entity RAT Radio Access Technology RRC Radio Resource
Control RRM Radio Resource Management SeGW Security Gateway SIR
Signal to Interference Ratio TDM Time Division Multiplexing UE User
Equipment DL Downlink--link from base station (dual FAP) to mobile
device UL Uplink--link from mobile device to base station (dual
FAP)
This application is based upon and claims the benefit of priority
from UK patent application No. 1410538.1, filed on Jun. 12, 2014,
the disclosure of which is incorporated herein in its entirety by
reference.
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